Wednesday, May 26, 2010

SPACE agencies may one day have Charles Darwin to thank for the longevity of their spacecraft. The life expectancy of a popular type of ion engine has been almost doubled using software that mimics the way natural selection evolves ever fitter designs.

Electrostatic ion engines are becoming popular in space missions. Instead of relying on burning large amounts of heavy liquid propellant for thrust, they use solar power to ionise a small supply of xenon gas. A high voltage applied across a pair of gridded electrodes sends the positively charged ions rushing at high speed towards the negative electrode. Most ions pass through the grid, generating thrust.

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He used evolution-mimicking software (...)

After 100 generations, the GA spawned a geometry/voltage set that boosted the ion engine grid's lifetime to 5.1 years - at least in the simulator (Journal of Propulsion and Power, DOI: 10.2514/1.44358). Factors optimised included grid hole diameter, hole spacing and the thickness of the grids. The engine could be improved further, says Farnell, by evolving the other parts too.